Lighted on-off switch



Jan. 20, 1970 E. B. MITCHELL ET AL LIGHTED ,ON-OFF SWITCH Filed March 5. 1968 2 Sheets-Sheet 2 IO 00 I2 7 V \T Q 74 Q/BO p h $76 y 4e Z 7O v F l G. 5

FIG. 3

EDWARD B. $213K? I BYPHILIP R. FELTON 68 ATTORNEY United States Patent Oflice 3,491,220 LIGHTED (IN-OFF SWITCH Edward B. Mitchell, Belmont, and Philip R. Felton,

Waltharn, Mass., assignors to United-Carr Incorporated, Boston, Mass., a corporation of Delaware Filed Mar. 5, 1968, Ser. No. 710,458 Int. Cl. H01h 9/16, 9/18 U.S. Cl. 200167 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The use of what may be referred to as cam operated switching means is not new in the art. The patent to Horn, US. 1,726,897, shows an early use of a cam device which utilizes a primary spring, in a hollow plunger, adapted to depress the operating member along an angular surface of the cam actuator. Simultaneously, a base plate of the plunger compresses a secondary spring fixed between it and the housing while sliding a bow element along a detent of the operating member. When the bow element passes the detent, the cam actuator rotates and either engages or disengages contact elements.

In the patent to Douglas, US. 2,047,940, a cam actuated switch is disclosed having a spring loaded plunger and a secondary spring circumscribed in spaced relation by the first spring which is placed between the operating member and the plunger. The two springs are separated by a casing wall and a button wall. This patent also discloses that the cam actuator may be spring loaded.

The Krieger patent, US 2,295,484, discloses a hollow plunger having a first spring engaging the plunger and the operating member and a secondary spring which engages the plunger and shoulders formed on the cam actuator.

In the Bentley patent, US. 2,576,771, the plunger mechanism comprises a primary compression spring which is engaged between the plunger head and an operating member and a secondary spring which engages between a spider, attached to the plunger, and plates acting as guides for the movable member. This mechanism includes a cam actuator.

The Raab patent which was issued in 1961 as US. 2,994,750 discloses a plunger mechanism which has a primary compression spring engaged between the plunger and a shoulder formed in the switch housing and a secondary spring which engages between the plunger and a spring seat 43 which is mounted on a lock bar 30 engaged with the operating member 40 which is engageable with the cam actuator.

In most cases where the design called for a lighted plunger, the means of carrying current to the bulb in the plunger was either through wires or through the use of some form of sliding contacts. The use of the sliding contact was brought about where the plunger was movable in relation to the housing proper and where this movement would not allow the convenient use of wires as 3,491,220 Patented Jan. 20, 1970 a means of providing current. The inventor has utilized a pair of parallel springs which allow movement of the plunger and even provide a return means while also acting as current carrying members.

SUMMARY OF THE INVENTION This invention relates to a switch mechanism of the cam actuated type wherein the operating member is held in position between upper and lower springs. It also relates to a switch mechanism having a lighted plunger which uses springs as a means of carrying current to the plunger from terminals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the switch with the cap and lens shown in section;

FIG. 2 is a section taken on line 2-2 of FIG. 1;

FIG. 3 is a section taken on line 3-3 of FIG. 1;

FIG. 4 is a plan vieW of the lower portion of the switch shown in FIG. 1 including the switch terminals and the switching bar; and

FIG. 5 is a section taken on line 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The switch comprises a plunger assembly, a housing, an actuating assembly and terminals.

The plunger assembly has a lens 10 in the form of a rectangular box whose open side is closed off by a base portion 12. The base portion 12 is formed of an insulating material, snap engaged to the lens 10 and has a pair of barriers 14 in spaced relation to each other extending from a surface thereof between which a bulb 16 is placed, as shown in FIG. 1. An integral, centrally located, arced or dome-shaped portion 18 extends from the opposite surface of the base portion 12 for a purpose to be set forth hereinafter. Eyelets 20 and 22 are passed through apertures formed in the base portion 12. Each of the eyelets 20, 22 are engaged to the base portion 12 close to an end thereof and fixes a brass washer 24, through which it is passed, to the external surface of the base portion 12 as shown in FIG. 1. The washer 24 has a larger diameter than the eyelets 20, 22 and forms a shoulder with it. One of the leads of the bulb 16 is wrapped around the portion of the eyelet 20 which extends into the cavity of the lens 10 while the other lead of the bulb 16 is Wrapped around the portion of the eyelet 22 extending into the cavity of the lens 10.

A flanged portion 25 extends from each of the short walls of the lens 10 in close proximity to the open side and to the engagement with the base portion 12.

The housing 26 includes a rectangular base 28 having a side wall 30, extending from the surface, along each long side in spaced relation to each other. Each of the side walls 30 has a rectangular projection extending inwardly separating the housing cavity into an upper portion, a midportion and a lower portion. The midportion is divided into three channels by a pair of Wall portions 32 which are in spaced parallel relation to each other and the side walls 30. The wall portions 32 are integral and extend from a rectangular barrier portion 34 which eX- tends around the lower cavity portion forming a narrow slot with each of the side walls 30 and almost completely closing olf the bottom of the lower cavity portion as shown in FIG. 1. A cap portion 36 extends from the base 28 at a short edge of the upper cavity portion in abutting right angle relationship to the side walls 30 defining an opening through which the lens extends and forming an inner shoulder 38 with the side walls 30. A shoulder 40 is formed on each of the wall portions 32 on the surfaces facing each other, a predetermined distance from the base 28. The passageway between the midportion and the lower portion of the housing cavity is formed by extensions of the shoulders 40. This passageway allows the shank of the actuator member 44 to pass therethrough but has a diameter smaller than the diameter of the secondary compression spring 46. On assembly, the secondary spring will therefore be trapped between the head of the actuator member 44 and the shoulders formed adjacent the aperture leading into the lower portion of the housing cavity.

The actuating assembly comprises a primary or upper compression spring 42, a movable member 44, a secondary or lower compression spring 46, a pair of spring members 48 and a cam 50.

The cam 50 comprises a generally rectangular cubic form having an upper surface with a flat land portion 52 at each end and'a triangular form 54 set between and spaced from the land portions 52. The triangular form 54 has a rounded apex and its legs define a first cam surface 56 and a second cam surface 58. The lower surface of the cam 50 has a slanted or angled surface 60 at each end and each of its side walls has a pair of spaced transverse ribs 62 extending therefrom as shown in FIGS. 1 and 4. A cylindrical protuberance 64 extends from the center of the forward surface of the cam 50 and a tubular cavity 66 is formed in the rear wall of the cam 50 with its axis coincident with the axis of the protuberance 64. There is a spring cavity 69 formed in close proximity to each short side edge of the cam 50.

The movable member 44 is of T-shaped configuration having an arced cap whose terminal ends are rounded and having a shank which terminates in a truncated point.

To assemble the switch, the lens assembly is placed into the housing cavity with its flanged portion butted against the inner shoulder 38 which is provided by 'the cap portion 36. A bulb terminal 67 is dropped into the slot formed between the sidewall and the barrier portion 34 and includes a right angled bend and a terminal end which extends into one of the channels defined by a wall portion 32. A spring member 48 is now placed under compression butted against the shoulder formed by the eyelets 20, 22 and the washer 24 and having its other terminal end butted against the right angled termination of the bulb terminal 67. The spring members 48 also act as current carrying members in the lamp circuit. The movable member 44 is held within the switch by first placing the primary compression spring into abutting relationship with the base portion 12 and into circumscribing relationship with the dome-shaped portion 18. Its other terminal end buts against the arced cap portion of the operating member 44. The secondary compression spring 46 is butted against the under surface of the cap portion of the operating member 44 and circumscribes in spaced relation to its shank. The two rounded terminal ends of the cap portion of the actuator member 44 rides on the shoulders formed in the wall portions 32. The actuator member 44 is thus floated within the switch assembly. A pair of switch terminals 68 pass through apertures formed in the bottom wall of the barrier portion 34 and extend upwardly into the lower cavity of the housing 26. A contact bar 70 comprising an engagement portion which is generally rectangular in form and has at each of its short ends an extension which is adapted to engage between the rib 62 and which has an aperture through which the protuberance 64 extends. A spring 74 is located in each of the spring cavities 69 and bears against the contact bar 70 and is trapped in the recess formed therein. The springs 74 bias the contact bar 70 into an effective physical contact with the switch terminals 68. A cylindrical protuberance extends from the base 28 of the lower cavity portion of the housing 26 and into the tubular cavity 66 of the cam 50 with one portion of the contact bar engaged against one of the switch terminals 68 and another portion of the contact bar 70 engaged against the other switch terminal 68 but adapted to be disengaged On movement of the cam 50 from one position to another as will be set forth more fully hereinafter. To complete the assembly of the switch, a cover (not shown) is placed on the housing in spaced parallel relationship with the base 28.

To operate the switch, the lens 10 is depressed which in turn applies a force to the primary compression spring 42 resulting in a compression of the secondary compression spring 46 and a movement of the actuator member 44 along the shoulders 40 until the terminal end of its shank butts against, in the position shown in FIG. 1, the second cam surface 58 which guides the terminal end of the shank down into the trough between the triangular form 54 and the land portion 52. At this point, the actuator member 44 exerts a downward rotating force against the angled surface 72 of the land portion 52 rotating the cam 50 and disengaging the contact bar 70. When the lens 10 is released, the compressed spring members 48, primary compression spring 42 and secondary compression spring 46 spring back returning the lens 10 to its original position and disengaging the actuator member from the cam. At this point, the cam is in the position as shown in FIG. 1 in phantom with the apex of the triangular form 54 on the opposite side of the shank of the actuator member 44 from that position in which it was originally at the start of the switching action. The cam 50 is prevented from over-rotation by having its angled surface 60 brought into abutting relationship with the inner surface of the barrier portion 34 and having the upper surface of the portion 52 butted against the upper inner surface of the barrier portion 52 as shown in FIG. 1.

With reference to the foregoing description, it is to be understood that what has been disclosed herein represents several embodiments of the invention and is to be construed as illustrative rather than restrictive in nature and that the invention is best described by the following claims.

We claim:

1. A switch assembly comprising a plunger movably related to a housing, the housing having a cavity formed therein, the cavity having a cam member associated therewith, an actuating assembly having a primary spring and a secondary spring holding a movable member therebetween, the movable member of T-shaped configuration having an upper surface and a shank portion, the primary spring abutting against the upper surface and the secondary spring circumscribing the shank portion, and the actuating assembly lying within the cavity between the plunger and the cam member and adapted to drive the movable member toward the cam member when the plunger is depressed and the cam member having a contact attached thereto and being adapted to move the contact into engagement with a contact in the cavity.

2. A switch assembly as set forth in claim 1 wherein the cam member is rotatable in relation to the housing and comprises an upper surface having a land portion at each end and a triangular form therebetween, the triangular form and the land portions having surfaces against which the shank of the movable member engages thereby turning the cam member from a first position to a second position.

3. A switch assembly as set forth in claim 1 wherein said plunger has a bulb mounted therein and the cavity of the housing has a pair of terminals mounted therein and a pair of springs mounted between the plunger and the terminals, the springs being compressible by the plunger and forming the electrical connection between the bulb and the terminals.

4. A swich assembly comprising a plunger movably related to a housing, the housing having a cavity formed therein, the cavity having a cam member associated therewith, an actuating assembly having a primary spring and a second spring holding a movable member therebetween, the actuating assembly lying within the cavity between a plunger and the cam member and adapted to drive the movable member toward the cam member when the plunger is depressed and the cam member having a contact attached thereto and being adapted to move the contact into engagement with a contact in the cavity; said plunger having a bulb mounted therein and the cavity of the housing having a pair of terminals mounted therein and a pair of springs mounted between the plunger and the terminals, the springs being compressible by the plunger and forming the electrical connection between the bulb and the terminals.

References Cited UNITED STATES PATENTS Horn 200-68 Krieger. Bentley. Raab 20068 Golbeck.

Kohl 20068 HERMAN o. JONES, Primary Examiner 

